Gene Editing Technology Could Have Serious Consequences, Researchers Say

Scientists have developed a method for editing the genes of practically any plant or animal. This method, known as CRISPR, allows researchers to fix genetic defects that cause disease in humans, for example. However, modified genes are spreading through entire populations faster than researchers thought possible and this poses serious biological risks, according to a new study.

Researchers from Cornell University developed a mathematical model that identifies "gene drive" or how quickly and extensively one of these modified genes spreads throughout a population, according to Business Insider. 

To test their model, researchers introduced a mutation, or allele, into a few individual fruit flies. Introducing an allele allows researchers to control malaria in mosquitos and pesticide resistance in plants, for example. However, the rate at which the allele spread suggests the gene editing system could spread to unintended species, according to the Cornell Chronicle.

"The time for these CRISPR alleles to spread and become fixed in a population is on the order of tens of generations," Rob Unckless, first author of the study and a postdoctoral research fellow in the Department of Molecular Biology and Genetics, told the Cornell Chronicle. "That's incredibly fast."

Compared to the CRISPR method, naturally occurring genes can take hundreds of generations to reach the same frequency.

"That's one of the things that is scary, if you imagine that one of these alleles gets into a population that you don't want it in," Unckless added.  

CRISPR is originally derived from a bacterial immune response, where RNA is used to defend against viruses. Essentially, the RNA breaks down specific DNA sequences of the pathogen's genome. Using the same premise, CRISPR allows researchers to edit specific genes in a way that will yield the desired effect, according to the release.

When a CRISPR allele is introduced to an organism, it then passes it to its offspring. This process continues throughout subsequent generations, which allows the modified gene to rapidly spread through populations. As a result, a CRISPR allele could end up in a population it wasn't originally intended for.  For example, a modified gene designed to control mosquitoes that carry certain diseases could end up in a related species. This would have more profound effects if the modified genes are passed between unrelated species, the researchers explained.

"There is so much we don't know, but it's also so promising," Unckless said in the release. "Nobody has done the modeling, so we are working on this."

Their study was recently published in the journal Genetics. 

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